- Participants will have two magnetic resonance imaging (MRI) scan sessions: one baseline scanning session before starting their rTMS sessions and a second scanning session after their last rTMS session . Part of each scanning session involves functional MRI (fMRI) scans. During the fMRI scans, participants will look at pictures related to cocaine use and pictures that are not related to cocaine use. Participants will also perform a simple decision task during the scans.